Follicies synthesize steroids not at a steady rate but in peaks throughout the cycle. Peaks of synthesis are not necessarily accompanied by release into the circulation. furthermore, it was found that the release of one of the three sex steroids is not accompanied by the release of the other two. The mechanisms controlling the differential synthesis and release will be investigated. Preliminary data also show that follicles of less than ovulatory size are steroidogenically more active than are those approaching ovulation. This will be investigated further. Since both alpha and bata subunits have been found able to cause steroidogenesis as well as ovulation in rabbits, work is being continued to determine whether these physiological effects are inherent in these subunits or whether they are due to contamination of the two subunits with LH.